Page:Encyclopædia Britannica, Ninth Edition, v. 8.djvu/195

Rh E N C- of the last century, was the first who attempted large pieces, but he was excelled by Henry Bone, R.A. Bone had been a china painter in the Plymouth and Bristol works ; and on his removal to London he applied his knowledge of vitrified pigments to enamel painting. Excelling all his predecessors in the magnitude of his plates, he ventured on subjects so large that in 1810 he {tainted a noble plaque measuring 18 inches by 16 inches. This master-piece was a copy of Titian s famous Bacchus and Ariadne, in the National Gallery, and was purchased by Mr Bowles of Wanstead for 2200 guineas. Bone s chief works were a series of portraits of celebrities of the Elizabethan period, which were sold by auction on the artist s death in 1834. (See BONE, vol. iv. p. 32.) Enamelling was also prosecuted by his son, H. P. Bone, who executed a very large Madonna and Child, and by his grandsons, W. Bone and C. R. Bone, -both of whom are recently deceased. The art of enamel painting was also carried on by A. Essex, but of late years it has not been extensively cultivated in this country. In con nection with remarkable enamels it should be mentioned that a painting of the Holy Family, after Parmigiano, was executed by C. Muss on a plaque measuring as much as 20 inches by 15 inches. This noble work was purchased by George IV. for 1500 guineas. In order to prepare a plate for the artist, a thin piece of gold or of copper is carefully annealed, and then coated with a dead white enamel. The enamel is imported in cakes from Venice, and is made from a mixture of silica, borax, and stannic oxide. After the plate has been fired, -a second coating of enamel is applied, and the plate returned to the oven. It is afterwards coated for the third time, but now with a more easily fusible glass, which is known in the workshop as &quot;flux.&quot; This is also imported from Venice, in the form of tubes and beads, and is employed to produce a brilliant lustre on the surface. The ground having been thus prepared is carefully ground smooth, and is then ready for the aitist. The colours which he employs consist of various metallic oxides mixed with the flux ; but it is obvious that the enameller s palette must be limited, since he is able to employ only such substances as are permanent at the temperature to which the plate will be subjected in the muffle. Blue colours are produced by means of oxide of cobalt ; violet by oxide of manganese ; green by cupric oxide or by chromic oxide ; red either by cuprous oxide, which is difficult to work in the oven, or by the preparation of gold known as purple of Cassius, which also produces a fine purple ; yellow by oxide of silver, oxide of lead, or an alkaline antimoniate ; brown by ferric oxide ; and black by ferrous oxide, or by means of cobalt and manganese, which have intense tinctorial power, and produce dense colours. Special recipes will be found in technical treatises, and need not be inserted here. The powdered colours of the enameller are mixed with oil of lavender or spike and spirit of turpentine, as a vehicle, and are applied to the enamel.-ground by means of a camel s-hair pencil. After each layer has been spread over the surface, the plate must be fired, and highly-finished work may have to pass through the oven a score of times. Once vitrified, the colours are permanent; hence the artist has no opportunity of correcting faults, except by the tedious process of grinding away a portion of the plate. Since the tints may be greatly modified by too high a temperature, the greatest care is needed in managing the furnace. In return for the great labour and risk involved in enamelling, the artist secures permanence for his work, the painting being always as fresh as when first executed ; it is indeed a painting in glass. In the middle of the last century the art of enamelling was largely applied to the decoration of snuff-boxes, patch- boxes, tea-canisters, candlesticks, needle-cases, labels for wine-bottles, and a variety of other small articles. The manufacture was established by Mr S. T. Janssen at York House, Battersea, near London, about the year 1750. The objects were usually made of copper ; and having been coated with an opaque white enamel, were decorated with Watteau subjects and floral and other designs, painted in enamel colours. A peculiar rose-tint was a favourite colour at Battersea. Advantage was also taken of the process of transferring engravings from copper-plates to glazed surfaces a process which was introduced about the year 1750 by Sadler and Green of Liverpool, and was E N C 185 largely employed for the decoration of pottery and porcelain. It is known that a manufacture of small enamelled objects, similar to those made at Battersea, but usually decorated in coarser style, was carried on by George Brett at Bilston in South Staffordshire. Splendid snuff boxes and other ornamental articles in enamelled work were also turned out by artists in France and Germany. Of late years the art of enamelling has been extensively applied to the coating of iron vessels for domestic purposes, with the view of keeping a clean surface and preventing the rusting of the metal. As far back as 1799, a process for this kind of enamelling was introduced by Dr Hickling ; and within the last thirty years a large number of patents have been granted for similar purposes. One of the most extensively used processes is that of Charles Henry Paris, which was introduced into England in 1850, and is now largely worked at Birmingham. The rnetal articles are first cleaned with dilute sulphuric acid, and powdered glaze is then sifted upon the clean surface. Adhesion of the powder is secured by applying to the iron a coating of gum-water. The object is then dried in an oven, whence it is transferred to the enamelling-furnace, where it is heated until the fused glaze flows evenly over the surface. After removal from the oven, the objects are allowed to cool with extreme slowness. It is often found necessary to apply a second coating of enamel. Paris s composition consists of 130 parts of cullet or broken glass, 20i parts of carbonate of sodium, and 12 parts of boracic acid. This forms the fundamental glaze, upon which variously coloured enamels may be employed. If enamelled vessels are to be used for culinary purposes, great care must be taken that the glass contains no lead, the presence of which would be highly dangerous. Acids often find their way through the pores of an enamel to the subjacent metal, and, spreading out between the iron and the glaze, cause the enamel to peel off. Exposure to sudden changes of temperature also tends to injure the enamel. Enamelling of a similar character is now largely used for street plates, name-plates at railway stations, advertising tablets, and other objects where permanent lettering is required. The insides of baths, cisterns, and boilers are also protected by enamelling ; and it has been proposed to prevent the fouling of ships bottoms by a coating of enamel. In 1871 a patent was granted to Mr Neilson of Glasgow for enamelling large metal objects, to which the process had not been previously applied, and also for improvements in the mechanical appliances needed for the transference of large objects in and out of the enamelling oven. For the history of enamelling see M. Labarte s Recherches sur la Pcinture en Otmail (Paris, 1856). This is incorporated in the author s Histoire dcs Arts industriels au Moyen Age (vol. iii. 2d. ed. Paris, 1875). See also, the Marquis de Laborde s Notice dcs Emaux exposes dans Icsgalcrics du Musee du Louvre (Paris, 1852). English leaders will find an admirable sketch of the history in Mr Franks s Observations on Glass and Enamel, extracted from the Art Treasures of the U. K. For details of old processes the works of Neri and Benvenuto Cellini may be consulted. Valuable papers will be found in the Archccolog. Journ. (vol. ii. p. 154), by Albert Way; Journ. Arch. Assoc. (vol. iii. p. 280), by W. H. Eogers ; and Art Journal for 1851, by A. Essex. The&quot; following works are also deserv ing of notice M. Reboulleau s Noveau Manuel complet de la pcinture en verre sur porcelaine et sur imail (new edy by M. Mamiier, Paris, 1866), and M. Claudius Popeliu s Wmail dcs Pcintrcs (Paris, 1866). (F- W. R.*) ENCAUSTIC PAINTING. The name encaustic is applied to paintings executed with vehicles in which wax is the chief ingredient. The term was appropriately applied to the ancient methods of painting in wax, because these required heat to effect them. Wax, however, may now be used as a vehicle for painting without heat being requisite : nevertheless the ancient term encaustic has VIII. 24